Field of the Invention
The present invention relates to the biological production of aromatic carboxylic acid and its derivatives. More particularly, the present invention relates to a process of biologically producing aromatic carboxylic acid and its derivatives by degrading lignin through chemical or biological conversion and biologically converting the lignin breakdown product into aromatic carboxylic acid or derivatives thereof.
Description of the Related Art
Today's chemical industry is highly dependent on crude oil as a feedstock to produce almost every commodity chemical or material. Aromatic hydrocarbons are among the most important raw materials in the chemical industry, and are obtained exclusively from fossil resources.
Benzoic acid, which is structurally the simplest among aromatic carboxylic acids, is used as intermediate for the manufacture of caprolactam, terephthalic acid, dyes and perfumes, and as a preservative in food and drugs. In addition, oxidative decarboxylation of benzoic acid is an important route in the manufacturing of phenol. Phenol is used mainly in the production of phenolic resins and bisphenol A.
Benzoic acid is prepared industrially by liquid-phase oxidation of toluene in the presence of cobalt or manganese naphthenic acid catalysts. However, increases in crude oil prices results in high manufacturing costs for aromatic raw materials, such as toluene. Furthermore, conventional petroleum-based benzoic acid production is recognized as nonrenewable and generates a lot of greenhouse gases. In this context, there is an increasing demand for an alternative route for benzoic acid production via industrial biotechnology using renewable biomass as feedstock.
WO 2012006039 discloses a process for producing a renewable benzoic acid, comprising dehydrogenating cyclic monoterpene into p-cymene, followed by contacting p-cymene with benzene to yield toluene, and oxidizing toluene into renewable benzoic acid. However, the oxidation of toluene into benzoic acid is carried out using a conventional chemical conversion process.
Elena et al. describes the synthesis of benzoic acid by formic acid-mediated didehydroxylation (Elena et. al., ChemSusChem. 3(7):811-3). However, the final product undergoes sublimation deposition during distillation. To avoid this problem, the usable solvents are limited.
There is, therefore, a strong need for a biological process of producing benzoic acid from renewable biomass.